The guide rails for the rollers or guide wheels of road vehicles assume different technical forms depending upon the type, angle, and cross-section profile of the guide wheels, as well as their general configuration.
The present invention concerns angled or even horizontal guide wheels used in pairs for travel along a rail adapted for that purpose. More specifically (but not exclusively), it applies to guide wheels angled as a downward pointing V, each wheel having a peripheral shoulder traditionally called a flange, similar to railway wheels.
For guiding movement, each guide wheel in a pair of guide wheels contact the sides of a guide rail as they move and in certain cases, they are locked onto the sides of the rail.
There is a need for improvement in both the quality and safety of guided travel. In prior art embodiments, maintaining the guide wheels tightly in contact with the sides of the guide rail assured safety and quality. Often a vertical precharge was also used to prevent the wheels from occasionally lifting unexpectedly during operation.
According to these prior art embodiments, the guide wheels were extracted by separating them, either by making use of the flexible force pressing the wheels together, or unlocking them and temporarily separating them while pulling them up. This operation required a means for separating the guide wheels enough to disengage them from the rail, or requires the guide wheels to be shaped and constructed so that a single vertical force could be used to extract them.
The quality and safety of guided movement can be improved remarkably by using guide wheels with a peripheral projection or a portion of the body which moves along below the linear rim of the rail head. This is the case with flanged guide wheels which operate at an angle, with the flange positioned below the rim. Another example might be simple guide wheels that move beneath the rail head, for example, along the rail web.
While these guide wheels provide secure guided travel, the projections protruding from the rail, that is, the sides of the rail head, form an obstacle when raising the guide wheels. In order to raise the wheels, there must be some means for either changing their angle, separating them, or accomplishing both of these movements either simultaneously or successively.
Incorporating these functions complicates the design of the guide wheels, requiring additional functions to take place in small, awkward spaces.
Public transportation and companies dependent upon guided travel impose many demands that must be fulfilled simultaneously, while at the same time attempting to simplify operation and design and improve safety and reliability:
First and foremost are acquisition and operation costs, which are important purchase conditions;
Second, the guaranteed reliability and safety of guide wheels which cannot physically slip out of the rail during operation; and
Finally, simplified operation, with a quick, simple method of disengaging the wheels from the rail and subsequently raising the guide assembly.
The goal of the present invention is to propose a satisfactory solution which allows the guide wheels to freely engage and disengage from the rail, either when stopped or when moving, in the case of guide assemblies using a pair of guide wheels, especially (but not exclusively) flanged guide wheels angled at a V.
To achieve this, the invention relates to a guide rail for angled guide wheels used in pairs and laterally engaging the guide rail, each guide wheel having a flange to prevent derailment, characterized in that the rail has certain areas where the guide wheels can be removed from the rail when subjected to a lifting force, but the guide wheels remain in contact with these areas as they are displaced during normal travel.
The multiple advantages of the invention concern the simplified design of the guide assembly, the guide wheel engagement-disengagement action, and reliable performance during guided travel.
First, the guide assembly is simplified due to the elimination of any device for separating the guide wheels.
Second, engaging and disengaging the guide wheels from the rail is accomplished by exerting only a simple vertical force which raises or lowers them in specific limited areas equipped with small slots, said areas either having visual markers or some other type of marker.
In addition, flanged wheels with a limited number of working parts are used to assure satisfactory performance.
Furthermore, it is no longer necessary to provide specific areas equipped to engage/disengage the guide wheels, since this can be accomplished by merely inserting a rail or a rail portion with slots at any given location for use when changing the guide mode.
Finally, the slots are simple to form and do not interfere with guide wheel movement, since they are shallow and limited in length; for this reason, they only reduce the width of the guide wheel path very slightly.